The Elevation Point Query Service returns the elevation in international feet or meters for a specific latitude/longitude (NAD 1983) point from the USGS 3DEP 1/3 arc-second layer hosted at the NGTOC. If unable to find data at the requested point, this service returns -1000000. Input parameters: x (longitude), y (latitude), units (Feet, Meters), output (XML, JSON). Latitude and longitude must be specified in decimal degrees with southern latitudes and western longitudes represented as negative values. The 1/3 arc-second dataset covers nearly all the U.S. states and territories, though Alaska has only partial coverage. For additional information, such as for 3DEP metadata, projection, horizontal/vertical datum, and vertical accuracy, go to FAQs:
- https://www.usgs.gov/faqs/what-metadata-are-available-3dep-products
- https://www.usgs.gov/faqs/what-are-projection-horizontal-and-vertical-datum-units-and-resolution-3dep-standard-dems
- https://www.usgs.gov/faqs/what-vertical-accuracy-seamless-3dep-dems
HTTP GET
The following is a sample HTTP GET request and response. The placeholders shown need to be replaced with actual values.
GET pqs.php?x=string&y=string&units=string&output=string HTTP/1.1 Host: nationalmap.gov/epqs/pqs.php
HTTP/1.1 200 OK Content-Type: text/xml; charset=utf-8 Content-Length: length <?xml version="1.0"?> xml
HTTP POST
The following is a sample HTTP POST request and response. The placeholders shown need to be replaced with actual values.
POST pqs.php HTTP/1.1 Host: nationalmap.gov/epqs/pqs.php Content-Type: application/x-www-form-urlencoded Content-Length: length x=string&y=string&units=string&output=string
HTTP/1.1 200 OK Content-Type: text/xml; charset=utf-8 Content-Length: length <?xml version="1.0"?> xml
